The present invention relates generally to power supplies, and, more specifically, to current-programmed controlled switching power converter and method which allows for controlling average inductor current by monitoring a partial current in an output filter inductor.
Current-programmed control, a scheme in which the output of a switch-mode power supply (SMPS) is controlled by choice of the peak current in a switching transistor, finds wide applications due to its ease of implementation, fast transient response and inherent stability. The current in the switching transistor is representative of the output current scaled by the duty ratio of the switching transistor. However, due to the switching ripple current in inductive elements, controlling the peak current produces an error with respect to the average output current. This error affects the accuracy of the current control loop and diminishes the benefits of the control method. Moreover, the full inductor current required for average current control is not always readily accessible for sensing.
Therefore, it would be desirable to provide a system and method that overcomes the above problems.